diff --git a/trezorlib/client.py b/trezorlib/client.py
index b08eea2fa..a5dfff445 100644
--- a/trezorlib/client.py
+++ b/trezorlib/client.py
@@ -148,7 +148,7 @@ class TextUIMixin(object):
     def callback_WordRequest(self, msg):
         word = raw_input("Enter one word of mnemonic: ")
         return proto.WordAck(word=word)
-        
+
 class DebugLinkMixin(object):
     # This class implements automatic responses
     # and other functionality for unit tests
@@ -163,12 +163,13 @@ class DebugLinkMixin(object):
     def __init__(self, *args, **kwargs):
         super(DebugLinkMixin, self).__init__(*args, **kwargs)
         self.debug = None
+        self.in_with_statement = 0
 
         # Always press Yes and provide correct pin
         self.setup_debuglink(True, True)
         
         # Do not expect any specific response from device
-        self.set_expected_responses(None)
+        self.expected_responses = None
 
         # Use blank passphrase
         self.set_passphrase('')
@@ -181,7 +182,26 @@ class DebugLinkMixin(object):
     def set_debuglink(self, debug_transport):
         self.debug = DebugLink(debug_transport)
 
+    def __enter__(self):
+        # For usage in with/expected_responses
+        self.in_with_statement += 1
+        return self
+
+    def __exit__(self, *args):
+        self.in_with_statement -= 1
+
+        # Evaluate missed responses in 'with' statement
+        if self.expected_responses != None and len(self.expected_responses):
+            raise Exception("Some of expected responses didn't come from device: %s" % \
+                    [ pprint(x) for x in self.expected_responses ])
+
+        # Cleanup
+        self.expected_responses = None
+        return False
+
     def set_expected_responses(self, expected):
+        if not self.in_with_statement:
+            raise Exception("Must be called inside 'with' statement")
         self.expected_responses = expected
 
     def setup_debuglink(self, button, pin_correct):
@@ -195,14 +215,6 @@ class DebugLinkMixin(object):
         resp = super(DebugLinkMixin, self).call_raw(msg)
         self._check_request(resp)
         return resp
-
-    def call(self, msg):
-        ret = super(DebugLinkMixin, self).call(msg)
-
-        if self.expected_responses != None and len(self.expected_responses):
-            raise Exception("Some of expected responses didn't come from device: %s" % \
-                    [ pprint(x) for x in self.expected_responses ])
-        return ret
         
     def _check_request(self, msg):
         if self.expected_responses != None: